CN1191498C - Liquid radiation curable composition especially suitable for producing flexible cured articles by stereolithography - Google Patents

Abstract

A liquid radiation curable stereolithographic composition comprising: an actinic radiation curable and cationically polymerizable organic compound, a cationic initiator, a free radical photoinitiator, and at least 1 cationic modifier comprising at least 2 reactive groups per molecule or at least 1 polyether polyol component or mixtures thereof. The cationic reactive modifier has at least 1 extended segment having a molecular weight of at least about 100 but no greater than about 2,000. The polyether polyol component has a molecular weight greater than or equal to about 4,000. The use of the cationic active modifier and the polyether polyol modifier can greatly improve the flexibility and toughness of the cured product without damaging the exposure speed, precision and wet recoatability of the composition. The invention also relates to a process for producing cured products, in particular three-dimensionally shaped articles prepared by treating the above-described compositions with actinic radiation.

Description

Liquid radiation curable composition especially suitable for producing flexible cured articles by stereolithography

The present invention relates to a liquid radiation curable composition particularly suitable for the production of three-dimensionally shaped articles by stereolithography, a method of using such a composition for producing cured products, in particular three-dimensionally shaped articles by stereolithography.

The technique of producing complex three-dimensional shaped objects using stereolithography has been known for a long time. According to this technology, a liquid radiation-curable composition is used as a raw material to repeatedly solidify through two steps (a) and (b) in an alternating sequence to form a product of a desired shape; wherein in the first step (a), the A layer of a liquid radiation-curable composition, one boundary of which is the surface of the composition, cured by means of suitable radiation, generally preferably generated by a computer-controlled laser source, in the area corresponding to the desired complex shape of the article to be formed. In the surface area of the layer height of the cross-sectional area; step 2 (b), cover a new layer of liquid radiation curable composition on the cured layer, and then repeat the sequence of steps (a) and (b) until the completion of the A so-called raw model of the desired shape. Such raw models are generally not yet fully cured, so post-curing is usually necessary.

The mechanical strength (modulus of elasticity, breaking strength) of the green model, also known as green strength, constitutes an important property of the green model and depends mainly on the properties of the stereolithography-resin composition used. Other important properties of stereolithography-resin compositions include: high sensitivity to radiation used during curing, minimal warpage coefficient, allowing high-resolution green models. In addition, eg the pre-cured (or pre-cured) material layer should be easily wetted by the liquid stereolithographic resin composition and of course not only the raw model but also the final cured shaped article should have optimal mechanical properties. Another important property of cured products is high flexibility and toughness, which is reflected in elongation at break and Izod impact strength.

Liquid radiation curable compositions for stereolithography processing that meet at least some of the above requirements are described, for example, in US Patent No. 5,476,748, incorporated herein by reference. The so-called hybrid system compositions presented in the article comprise free-radical and cationic photopolymerizable components. Such mixed compositions contain at least:

(A) liquid 2-functional or higher functional epoxy resin or a liquid mixture of 2-functional or higher functional epoxy resin;

(B) a cationic photoinitiator or a mixture of cationic photoinitiators;

(C) a free radical photoinitiator or a mixture of free radical photoinitiators; and

(D) at least one liquid poly(meth)acrylate having a (meth)acrylate functionality greater than 2;

(E) at least 1 liquid diacrylate; and

(F) A polyol component selected from hydroxyl terminated polyethers, polyesters and polyurethanes.

Such hybrid systems may also optionally contain vinyl ether resins or other cationic curing components such as oxetanes, spiro-orthoesters, and the like.

As is known to those skilled in the art, most commercially available hybrid stereolithographic compositions suffer from very low elongation at break and very low Izod impact strength. The average values are at levels of about 4% and 0.45 ft.lb/in (ft.lb/in), respectively. Cured products made from such compositions are very brittle and cannot meet the requirements for rapid prototyping and application as verification models.

A comprehensive exploration was carried out to solve the problem of brittleness of cured products prepared from stereolithographic compositions. To date, these efforts have focused on acrylate-based compositions employing acrylate urethane oligomers or their lower molecular weight polymers as toughening agents. Urethane acrylate oligomers or polymers are known to be a highly flexible and tough (high Izod impact strength) material. Thus, incorporation of such molecules into acrylate compositions will result in soft, tough (durable) cured articles. The above-mentioned attempts use specific diluents: such as urethane acrylates, see European patent application 562,826, awarded to Loctite; For functional diluent monomers, see Japanese Patent Application No. 97-431498, issued to Mitsubishi Rayon Corporation; and for unsaturated urethanes, see Japanese Patent Application No. 97-466285, assigned to Takemoto Grease Company. Cured articles made from such compositions are soft and exhibit relatively high impact strength, sometimes approaching 1-1.3 ft.lb/in.

The main disadvantages of toughened acrylate urethane compositions are: 1) polymerization is hindered by atmospheric oxygen because the polymerization is free radical; 2) cure shrinkage is unacceptably large; and 3) acrylate urethane compounds Skin irritating, especially when its viscosity is low (low viscosity is highly preferred for stereolithography use). Efforts to incorporate acrylate urethane tougheners into hybrid stereolithographic compositions as a means of improving flexibility and toughness have not been successful. Such methods often slow down the exposure speed to unacceptable levels. The reduction in exposure speed is due to the fact that the acid produced by the dissociation of the cationic photoinitiator that polymerizes the epoxy ring or any other cationic curing compound reacts with the nitrogen of the urethane group and prevents cationic photopolymerization from occurring.

On the other hand, although cationic or hybrid cationic-radical stereolithographic compositions are able to alleviate the aforementioned acrylate chemistry problems, the cured articles are very brittle and exhibit very low toughness.

One technique for improving the flexibility of hybrid stereolithographic compositions employs low to medium molecular weight diols or triols or polyols, especially polyether polyols. This method has been used for many years and is still used. It relies on reducing the crosslink density of the three-dimensional network as a means of reducing the brittleness of the cured article. For example, an international patent application recently granted to DSM Corporation, Japan Synthetic Rubber Corporation and Japan Fine Coatings Corporation for a photocurable stereolithography resin composition, WO97/38354 (1997-10-16) discloses the use of polyether polyols To improve the elongation and toughness of three-dimensional products. Such polyether polyols have an average of about 3 or more hydroxyl groups per molecule. Examples of suggested polyether polyols include glycerol, pentaerythritol, trimethylolpropane, sorbitol, sucrose, either neat or ethylene oxide extended. The preferred molecular weight of the polyether polyol is about 100-2000, more preferably about 160-1000. The patent also discloses that "if a polyether polyol with an excessively large molecular weight is used, the mechanical strength of the three-dimensional product obtained by photoprocessing will be reduced."

However, the main disadvantages of this polyether polyol toughening method are 1) drastic reduction of thermal properties such as heat deflection temperature, glass transition temperature, 2) reduced rigidity of the cured article and 3) resistance of the cured article to water and humidity reduced capacity. Despite all these previous efforts, there remains a need for a stereolithographic composition that produces flexible, durable cured articles at a commercially acceptable speed of exposure and depth of cure.

A first aspect of the invention relates to a method for producing three-dimensional articles from a radiation curable composition using stereolithography. The composition is a mixture consisting of at least 1 cationically polymerizable compound and at least 1 free radically polymerizable compound, at least 1 photoinitiator for cationic and free radical polymerization and 1 active cationic modification as defined below agent (RCM). The solid or liquid cationically polymerizable compound in the radiation curable composition may be at least a polyglycidyl ether of the following compounds: aliphatic or cycloaliphatic or aromatic alcohols or polybasic acids, cycloaliphatic epoxides, formazan Phenol epoxy novolacs, phenol epoxy novolacs, vinyl ethers, lactones, spiro-orthoesters, oxetanes, acetals, cyclic thioethers, cyclic ethers or siloxane derivatives .

More specifically, the present invention relates to a liquid radiation-curable stereolithography composition, comprising 20-90 wt% of an organic compound curable by actinic radiation and capable of cationic polymerization, 0.05-12 wt% of a cationic initiator, 0.5-30 wt% of one Active cationic modifiers are defined below. The present invention relates to a liquid radiation curable composition for the manufacture of three-dimensionally shaped articles comprising:

a) 20-90% by weight of an organic compound curable by actinic radiation and capable of cationic polymerization;

b) 0.05～12wt% cationic photoinitiator;

c) 0.5 to 30 wt% of a cationic active modifier represented by the following formula

d) 0～10wt% free radical photoinitiator;

e) 0 to 40% by weight of free radical curable components containing at least one mono- or polyacrylate and/or methacrylate;

f) 0.5～30wt% polyhydric alcohol; And

g) 0-10 wt% customary additives.

The actinic radiation-curable and cationically polymerizable organic compound preferably comprises 10 to 80% by weight of at least one solid or liquid cycloaliphatic compound having at least 2 epoxy groups and an epoxy equivalent of 70 to 350 g/eq (gram/eq). polyepoxides, or mixtures thereof. Alternatively, the actinic radiation-curable and cationically polymerizable organic compound preferably comprises 3 to 70% by weight of solid or liquid polyglycidyl ethers of at least 1 of the following compounds: aliphatic or cycloaliphatic or aromatic alcohols or polybasic acids, Epoxy cresol novolacs, epoxy phenol novolacs, lactones, spiro-orthoester compounds, oxetane compounds having at least 2 cationically active groups per molecule; or mixtures thereof.

In another aspect, the actinic radiation-curable and cationically polymerizable organic compound comprises 0.5 to 40% by weight of at least 1 solid or liquid vinyl ether having at least 2 vinyl ether groups or at least 1 hydroxyl or epoxy Functionalized vinyl ether compounds.

The cationically curable component may be a mixture comprising: at least one polyglycidyl compound or cycloaliphatic polyepoxide or aromatic ring-containing, epoxy cresol novolac or epoxy phenol novolac A polyglycidyl compound containing an average of at least 2 epoxy groups per molecule; and at least 1 vinyl ether resin.

The curable composition optionally comprises from about 3 to 40% by weight of a free radical curable component comprising at least one mono- or poly(meth)acrylate. The polyfunctional (meth)acrylate preferably contains 2 to 7 acrylate groups on average.

The polyol or polyol (component (f)) may contain aliphatic, cycloaliphatic or substituted cycloaliphatic groups. Polyols may alternatively contain aromatic carbocycles in the molecule.

The present invention also relates to a process for preparing a cured product, wherein the composition described above is treated with actinic radiation. More preferably, the present invention relates to a method of preparing a three-dimensionally shaped article comprising subjecting the radiation curable composition described above to treatment with actinic radiation such that the surface area corresponding to the desired cross-sectional area of the three-dimensional article to be formed Inside, an at least partially cured layer is formed on the surface of the composition. The at least partially cured layer produced in step (a) is then covered with a new layer of radiation curable composition. Steps (a) and (b) are repeated until an article of desired shape is formed. Optionally, post-curing is performed on the obtained article.

The above and other aspects of the invention can be implemented alone or in combination. Other aspects of the invention will become apparent to those skilled in the art from a study of the disclosure herein.

The cationically curable liquid or solid compound is preferably a polyglycidyl compound or cycloaliphatic polyepoxide or epoxy cresol novolac or epoxy phenol novolac compound having an average of more than one Epoxy group (oxirane ring). Such resins may have an aliphatic, aromatic, cycloaliphatic, araliphatic or heterocyclic structure; they contain epoxy groups as side groups, or these groups form part of an alicyclic or heterocyclic system. Epoxy resins of this type are generally known and commercially available.

Polyglycidyl esters and poly([beta]-methylglycidyl) esters are examples of suitable epoxy resins. The polyglycidyl esters can be prepared by reacting a compound having at least 2 carboxyl groups in the molecule with epichlorohydrin or glycerol dichlorohydrin or β-methylepichlorohydrin. The reaction is conveniently carried out in the presence of a base. Compounds having at least 2 carboxyl groups in the molecule, in this case for example aliphatic polycarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid Or dimerized or trimerized linoleic acid. Likewise, however, it is also possible to use cycloaliphatic polycarboxylic acids, for example tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid. Aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, or carboxyl-terminated adducts such as trimellitic acid can also be used Adducts of triacids with polyols such as glycerol or 2,2-bis(4-hydroxycyclohexyl)propane.

Polyglycidyl ethers or poly([beta]-methylglycidyl) ethers can likewise be used. The preparation method of the polyglycidyl ether comprises, making a compound having at least 2 free alcoholic hydroxyl groups and/or phenolic hydroxyl groups and appropriately substituted epichlorohydrin under alkaline conditions or in the presence of an acid catalyst The reaction is carried out, followed by alkali treatment. Ethers of this type can be derived, for example, from acyclic alcohols such as ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, propane-1,2-diol or poly(oxypropylene ) diol, propane-1,3-diol, butane-1,4-diol, poly(oxytetramethylene) glycol, pentane-1,5-diol, hexane-1,6 -Diols, hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpropane, bis(trimethylolpropane), pentaerythritol, sorbitol and polyepichlorohydrin derivatives come. However, suitable glycidyl ethers can be prepared from cycloaliphatic alcohols such as 1,3- or 1,4-dihydroxycyclohexane, bis(4-hydroxycyclohexyl)methane, 2,2-bis (4-Hydroxycyclohexyl)propane or 1,1-bis(hydroxymethyl)cyclohex-3-ene, or they have an aromatic ring, such as N,N-bis(2-hydroxyethyl)aniline or p,p '-bis(2-hydroxyethylamino)diphenylmethane.

Particularly important typical examples of polyglycidyl ethers or poly(β-methylglycidyl)ethers are those based on phenols; or on monocyclic phenols, such as on resorcinol or hydroquinone or on poly Cyclophenols, e.g. based on bis(4-hydroxyphenyl)methane (bisphenol F), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) or on condensation products, can be obtained under acidic conditions from Obtained by condensation of phenol or cresol with formaldehyde, eg phenol novolac and cresol novolac resins. These compounds are especially preferred as epoxy resins according to the invention, especially based on diglycidyl ethers of bisphenol A and bisphenol F and mixtures thereof.

Poly(N-glycidyl) compounds are likewise suitable for the purpose of the invention and can be obtained, for example, by dehydrochlorination of the reaction product of epichlorohydrin with an amine containing at least 2 amine hydrogen atoms. Such amines are, for example, n-butylamine, aniline, toluidine, m-xylylenediamine, bis(4-aminophenyl)methane or bis(4-methylaminophenyl)methane. However, other examples of poly(N-glycidyl) compounds include N,N'-diglycidyl derivatives of cycloalkylene ureas, such as ethylene urea or 1,3-propylene urea and hydantoin Acylureides such as N,N'-diglycidyl derivatives of 5,5-dimethylhydantoin.

Poly(S-glycidyl) compounds are also suitable as cationically curable resins here, examples are di-S-glycidyl derivatives derived from dithiols such as ethane-1,2-dithiol or bis(4 -Mercaptomethylphenyl) ether derived.

Examples of those epoxy compounds in which the epoxy group forms part of a cycloaliphatic or heterocyclic ring include bis(2,3-epoxycyclopentyl) ether, 2,3-epoxycyclopentyl glycidyl ether , 1,2-bis(2,3-epoxycyclopentyloxy)ethane, bis(4-hydroxycyclohexyl)methane glycidyl ether, 2,2-bis(4-hydroxycyclohexyl)propane dishrinkle Glyceryl ether, 3,4-epoxycyclohexyl-methyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methyl-cyclohexylmethyl 3,4-epoxy -6-methylcyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)hexanedi ester, ethylene (3,4-epoxycyclohexane-carboxylate, ethylene glycol bis(3,4-epoxycyclohexylmethyl) ether, vinylcyclohexene dioxide, bicyclic Pentadiene diepoxide or 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,3-dioxane.

However, it is also possible to use epoxy resins in which the 1,2-epoxy groups are attached to different heteroatoms or functional groups. Examples of such compounds include N,N,O-triglycidyl derivatives of 4-aminophenol, glycidyl ethers/glycidyl esters of salicylic acid, N-glycidyl-N'-(2- Glycidyloxypropyl)-5,5-dimethylhydantoin or 2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin -3-yl) propane.

It is also conceivable to use liquid prereacted adducts between epoxy resins, such as those mentioned above, and hardeners for epoxy resins.

Of course, liquid mixtures of different epoxy resins can also be used in the novel compositions.

Examples of cationically polymerizable organic substances other than epoxy resin compounds include oxetane compounds such as trimethylene oxide, 3,3-dimethyloxetane, and 3,3-dichloromethyloxetane Butane, 3-ethyl-3-phenoxymethyloxetane, and bis(3-ethyl-3-methoxy)butane; oxolane compounds such as tetrahydrofuran and 2,3-dimethyl - tetrahydrofuran; cyclic acetal compounds such as trioxane (trioxane), 1,3-dioxolane (dioxalane) and 1,3,6-trioxane cyclooctane; cyclic lactone compounds such as β- propiolactone and ε-caprolactone; thiirane compounds such as thiirane, 1,2-propylene sulfide, and thiochlorohydrin; thiotane compounds such as 1,3 propylene sulfide and 3 , 3-Dimethylthiotane.

Vinyl ethers useful in stereolithographic compositions include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl Vinyl ether, cyclohexyl vinyl ether, butylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tert-butyl vinyl ether , tert-amyl vinyl ether, ethylhexyl vinyl ether, dodecyl vinyl ether, ethylene glycol divinyl ether, ethylene glycol butyl vinyl ether, hexanediol divinyl ether, diglycol Alcohol monovinyl ether, triethylene glycol methyl vinyl ether, tetraethylene glycol divinyl ether, trimethylolpropane trivinyl ether, aminopropyl vinyl ether, diethylaminoethyl vinyl ether, ethyl Glycol divinyl ether, polyalkylene glycol divinyl ether, alkyl vinyl ether and 3,4-dihydropyran-2-methyl 3,4-dihydropyran-2-carboxylic acid ester. Commercially available chain-extended vinyl ethers include Pluriol-E200 divinyl ether (PEG200-DVE), poly-THF290 divinyl ether (PTHF290-DVE), and polyethylene glycol-520 methyl vinyl ether (MPEG500-VE ), all supplied by BASF. Hydroxy-functionalized vinyl ethers include butylene glycol monovinyl ether, cyclohexanedimethanol monovinyl ether, ethylene glycol monovinyl ether, hexanediol monovinyl ether, polyethylene glycol monovinyl ether .

Another particularly important class of vinyl ethers suitable for use in stereolithography and useful in hybrid flexographic stereolithographic compositions are those all covered in US Patent No. 5,506,087, incorporated herein by reference. More preferred are the vinyl ethers supplied by AlliedSignal under the tradenames Vectomer 4010, Vectomer 5015, Vectomer 4020.

Other cationically curing compounds include spiro-orthoesters prepared by the reaction between epoxy compounds and lactones; ethylenically unsaturated compounds such as vinylcyclohexane, N-vinyl-2-pyrrolidone, and their various Such derivatives, isobutene and polybutadiene, and even derivatives of the above compounds.

The above-mentioned cationically polymerizable compounds may be used alone or as a mixture of 2 or more, depending on the properties required.

Other commercially available cationically curable products that can be used in the present invention include: Uvacure 1500, Uvacure 1501, Uvacure 1502, Uvacure 1530, Uvacure 1531, Uvacure 1532, Uvacure 1533, Uvacure 1534, Uvacure 1561, Uvacure 1562, all from UCB Radcure Corporation ( Commercially available from Smyrna, Georgia); UVR-6105, UVR-6100, UVR-6110, UVR-6128, UVR-6200, UVR-6216 (Union Carbide); Araldite GY series, a bisphenol A ring Oxygen liquid resins, Araldite CT and GT series, a bisphenol A epoxy solid resin, Araldite GY and PY series, a bisphenol F epoxy liquid resin, cycloaliphatic epoxy Araldite CY 179 and PY 284 , Araldite DY and RD reactive diluent series, Araldite ECN series of epoxy cresol novolac, and Araldite EPN series of epoxy phenol novolac, all of which are commercially available products of Ciba Geigy Specialty Chemicals Company; Shell Corporation Heloxy and Epon series; DER series - flexible aliphatic and bisphenol A liquid or solid epoxy resin, DEN series - epoxy novolak resin, all commercially available products of Dow Chemical Company; Celoxide 2021, Celoxide 2021P , Celoxide 2081, Celoxide 2083, Celoxide 2085, Celoxide 2000, Celoxide 3000, Glycidole, AOEX-24, Cyclomer A200, Cyclomer M-100, Epolead GT-300, Epolead GT-302, Epolead GT-400, Epolead GT-401, GT-40 EpoleadGT-403 (Daicel Chemical Industry Company), Epicoat 828, Epicoat 812, Epicoat872, Epicoat CT 508 (Yuka Shell Chemical Company), KRM-2100, KRM-2110, KRM-2199, KRM-2400, KRM-2410, KRM- 2408, KRM-2490, KRM-2200, KRM-2720, KRM-2750 (Asahi Denka Kogyo Company).

The present invention can be practiced using a wide variety of known and commercially tried and tested cationic photoinitiators for epoxy resins. Examples of these photoinitiators are onium salts formed with weakly nucleophilic anions. Examples thereof are halide, iodonium or sulfonium, sulfoxonium or diazonium salts, as described, for example, in US-A-3,708,296. Another class of cationic photoinitiators are metallocene salts.

Further reviews of common onium salt initiators and/or metallocene salts are published in UV Curing, Science & Technology (ed.: S.P. Pappas, Technology Transfer Corporation, 642 Westover Road, Stanford, Connecticut, USA) or in Coatings, Chemistry and Technology of UV and EB Formulations for Inks and Paints", Volume 3 (Editor-in-Chief: P.K.T. Oldring), which is hereby incorporated by reference.

Preferred compositions comprise a compound of general formula (B-I), (B-II) or (B-III) as cationic photoinitiator

wherein R _1B , R _2B , R _3B , R _4B , R _5B , R _6B and R _7B are independently C ₆ -C ₁₈ aryl groups, which may be unsubstituted or substituted with appropriate groups, and

A ^- is an anion of CF ₃ SO ₃ ^- or the general formula [LQ _mB ] ^- , where

L is boron, phosphorus, arsenic or antimony,

Q is a halogen atom, or, some of the groups Q in the anion LQ _mB ^- may also be a hydroxyl group, and

mB is an integer corresponding to the valence of L+1.

In this case, examples of the C ₆ -C ₁₈ aryl group are phenyl, naphthyl, anthracenyl and phenanthryl. Such substituents present in suitable groups are alkyl, preferably C ₁ -C ₆ alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, Tert-butyl or various isomers of pentyl or hexyl, alkoxy, preferably C ₁ to C ₆ alkoxy, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy or Hexyloxy, alkylthio, preferably C ₁ -C ₆ alkylthio, such as methylthio, ethylthio, propylthio, butylthio, pentylthio or hexylthio, halogen such as fluorine, chlorine, bromine Or iodine, amino group, cyano group, nitro group, or arylthio group, such as phenylthio group. Examples of preferred halogen atoms Q are chlorine, especially fluorine. Preferred anions LQ _mB ⁻ are BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ and SbF ₅ (OH) ⁻ .

Particularly preferred compositions are those comprising as cationic photoinitiator a compound of general formula (B-III), wherein R _5B , R _6B and R _7B are aryl groups, and among the aryl groups are in particular phenyl or bi Phenyl or a mixture of these two groups.

Preferred compositions are also those comprising as photoinitiator a compound of general formula (B-IV)

in

cB is 1 or 2,

dB is 1, 2, 3, 4 or 5,

X _B is a non-nucleophilic anion, especially PF ₆ ^- , AsF ₆ ^- , SbF ₆ ^- , CF ₃ SO ₃ ^- , C ₂ F ₅ SO ₃ ^- , nC ₃ F ₇ SO ₃ ^- , nC ₄ F ₉ SO ₃ ^- , nC ₆ F ₁₃ SO ₃ ^- and nC ₈ F ₁₇ SO ₃ ^- ,

R _8B is π-arene, and

R _9B is an anion of π-arene, especially a cyclopentadienyl anion.

Examples of π-aryl groups as R _8B and π-aryl anions as R _9B can be found in EP-A-0094915. Examples of preferred π-aryl groups as _R8B are toluene, xylene, ethylbenzene, cumene, methoxybenzene, methylnaphthalene, pyrene, perylene, stilbene, dibenzofuran and dibenzofuran Thiophene. Cumene, methylnaphthalene or stilbene are especially preferred. Examples of non-nucleophilic anions X ⁻ are FSO ₃ ⁻ , anions of organic sulfonic acids, carboxylic acids, etc., or anions LQ _mB ⁻ . Preferred anions are derived from partially fluorinated, perfluorinated-aliphatic or partially fluorinated or perfluorinated-aromatic carboxylic acids such as CF ₃ SO ₃ ^- , C ₂ F ₅ SO ₃ ^- , nC ₃ F ₇ SO ₃ ^- , nC ₄ F ₉ SO ₃ ^- , nC ₆ F ₁₃ SO ₃ ^- and nC ₈ F ₁₇ SO ₃ ^- , or, especially partially fluorinated or perfluorinated aliphatic or partially fluorinated or perfluorinated Fluorinated aromatic organic sulfonic acids such as C ₆ F ₅ SO ₃ ⁻ , or preferably anions LQ _mB ⁻ , such as BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ and SbF ₅ (OH) ⁻ . Preferred are PF ₆ ^- , AsF ₆ ^- , SbF ₆ ^- , CF ₃ SO ₃ ^- , C ₂ F ₅ SO ₃ ^- , nC ₃ F ₇ SO ₃ ^- , nC ₄ F ₉ SO ₃ ^- , nC ₆ F ₁₃ SO ₃ ^- and nC ₈ F ₁₇ SO ₃ ⁻ .

Metallocene salts can also be used in combination with oxidizing agents. Such combinations are described in EP-A-0126712.

In order to improve the light yield, according to the type of initiator, a sensitizer can also be used. Examples of these are polycyclic aromatic hydrocarbons or aromatic ketone compounds. Specific examples of preferred sensitizers can be found in EP-A-0153904.

More preferred commercially available cationic photoinitiators are UVI-6974, UVI-6970, UVI-6960, UVI-6990 (manufactured by Union Carbide Corporation), CD-1010, CD-1011, CD-1012 (manufactured by Sartomer Company), Adekaoptomer SP-150, SP-151, SP-170, SP-171 (manufactured by Asahi DenkaKogyo), Irgacure 261 (Ciba-Geigy Specialty Chemicals), CI-2481, CI-2624, CI-2639, CI- 2064 (Nippon Soda Company), DTS-102, DTS-103, NAT-103, NDS-103, TPS-103, MDS-103, MPI-103, BBI-103 (Midori Chemical Company). Most preferred are UVI-6974, CD-1010, UVI-6970, Adekaoptomer SP-170, SP-171, CD-1012 and MPI-103. The above cationic photoinitiators may be used alone or in combination of two or more.

Any type of photoinitiator that generates free radicals upon exposure to appropriate radiation can be used. Typical examples of free radical photoinitiators are benzogens such as benzoines, benzoine ethers such as benzoine methyl ether, benzoine ethyl ether and benzoine isopropyl ether, benzoine benzene Base ethers and benzoyl acetates, acetophenones, such as acetophenone, 2,2-dimethoxy-acetophenone and 1,1-dichloroacetophenone, benzil, benzil ketals such as benzil dimethyl ketal and benzil diethyl ketal, anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-Amylanthraquinone, but also triphenylphosphine, benzoylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide ( ^Luzirin® TPO), bis-acylphosphine oxide substances, benzophenones, such as benzophenone and 4,4'-bis(N,N'-dimethylamino)benzophenone, thioxanthone and xanthenone, acridine derivatives, phenazine derivatives , quinoxaline derivatives or 1-phenyl-1,2-propanedione 2-O-benzoyl oxime, 1-aminophenyl ketone or 1-hydroxyphenyl ketone, such as 1-hydroxycyclohexylphenyl Ketone, phenyl 1-hydroxyisopropyl ketone, and 4-isopropylphenyl 1-hydroxyisopropyl ketone are all known compounds.

Particularly suitable free radical photoinitiators customarily used with He/Cd laser sources are acetophenones such as 2,2-dialkoxybenzophenone and 1-hydroxyphenyl ketones such as 1-hydroxycyclohexylbenzene ketone or 2-hydroxy-cumyl phenyl ketone (=2-hydroxy-2,2-dimethylacetophenone), but especially 1-hydroxy-cyclohexyl phenyl ketone.

One class of photoinitiators commonly used when employing an argon ion laser includes benzil ketals, such as benzyl dimethyl ketal. In particular, the photoinitiators used are α-hydroxyphenylketone, benzildimethylketal or 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

Another class of suitable photoinitiators are ionic dyes-counterionic compounds that absorb actinic radiation and generate free radicals capable of initiating acrylate polymerization. In this way, the novel composition comprising the ionic dye-counter ionic compound can be cured controllably within a certain range by visible light with an adjustable wavelength range of 400-700 nm. Ionic dye-counter ionic compounds and their mode of action are known, see for example US Patents 4,751,102, 4,772,530 and 4,772,541. Examples of suitable ionic dye-counterionic compounds are anionic dye-iodonium ion complexes, anionic dye-pyrenium ion complexes, especially cationic dye-borate anionic compounds of the general formula:

where D _c ⁺ is a cationic dye, and R _1C , R _2C , R _3C and R _4C are independently of each other alkyl, aryl, alkaryl, allyl, aralkyl, alkenyl, alkynyl and aliphatic A cyclic or saturated or unsaturated heterocyclic group. Preferred definitions of the radicals R _1C to R _4C can be found, for example, in EP-A-0223587.

The novel composition preferably comprises 1-hydroxyphenylketone, especially 1-hydroxycyclohexylphenylketone, as photoinitiator.

The free radical and cationic photoinitiator should be added in an effective amount, that is, based on the total amount of the composition, the amount used is 0.1-12, especially 0.5-9 wt%. If the novel composition is to be used in the stereolithography process that typically employs a laser beam, it is important that the light-absorbing capacity of the composition be matched by the choice of photoinitiator type and content in order to achieve a cure depth in the medium range at normal laser rates. About 0.1 ~ 2.5mm.

The new mixture also contains various photoinitiators with different sensitivities to different wavelengths of radiation or radiation, in order to obtain better utilization of UV/visible light sources emitting different wavelengths of radiation. In this connection, it is advantageous to select the various photoinitiators and their corresponding amounts to produce the same degree of light absorption for the various radiations used.

The optional radically curable component preferably comprises at least one solid or liquid multi(meth)acrylate, such as di-, tri-, tetra- or pentafunctional monomers or oligomeric aliphatic, cycloaliphatic or Aromatic acrylate or methacrylate. The preferred molecular weight of the compound is between 200-500.

Suitable aliphatic multi(meth)acrylates are the triacrylates or trimethacrylates of: hexane-2,4,6-triol, glycerol or 1,1,1-trimethylolpropane , ethoxylated or propoxylated glycerol or 1,1,1-trimethylolpropane; The hydroxyl-containing tri(meth)acrylate obtained by the reaction. It is also possible to use, for example, tetraacrylate of pentaerythritol, tetraacrylate of ditrimethylolpropane, monohydroxytriacrylate or -methacrylate of pentaerythritol, or monohydroxypentaacrylate or -methacrylate of dipentaerythritol ester.

In addition, it is also possible to use, for example, polyfunctional urethane acrylates or urethane methacrylates. Such urethane (meth)acrylates are known to the person skilled in the art and can be prepared in a known manner, for example by reacting hydroxyl-terminated polyurethanes with acrylic or methacrylic acid, or by prepolymerizing isocyanate-terminated Compounds react with hydroxyalkyl (meth)acrylates to generate corresponding urethane (meth)acrylates.

Examples of suitable aromatic tri(meth)acrylates are the reaction products of trihydric phenols and triglycidyl ethers of phenol or cresol novolaks containing 3 hydrocarbyl groups with (meth)acrylic acid.

"(Meth)acrylates" as used herein are known compounds and some are commercially available, for example from the company SARTOMER under trade names such as ^SR® 295, ^SR® 350, ^SR® 351, ^SR® 367, ^SR® 399, ^SR® 444, ^SR® 454, ^SR® 9041 were obtained.

Preferred compositions are those comprising a free radical curable component comprising tri(meth)acrylates or penta(meth)acrylates.

Suitable examples of di(meth)acrylates are di(meth)acrylates of the following compounds: cycloaliphatic or aromatic diols such as 1,4-dihydroxymethylcyclohexane, 2,2-bis(4 -Hydroxy-cyclohexyl)propane, bis(4-hydroxycyclohexyl)methane, hydroquinone, 4,4'-dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol S, ethoxylated or propoxylated oxylated bisphenol A or ethoxylated or propoxylated bisphenol F or ethoxylated or propoxylated bisphenol S. Such di(meth)acrylates are known and some are commercially available.

Other di(meth)acrylates that can be used are compounds of the general formula (F-I), (F-II), (F-III) or (F-IV)

in

R _1F is a hydrogen atom or a methyl group,

Y _F is a direct bond, C ₁ ~ C ₆ alkylene, -S-, -O-, -SO-, -SO ₂ - or -CO-,

R _2F is a C ₁ to C ₈ alkyl group or a phenyl group, the latter may be unsubstituted or substituted with one or more C ₁ to C ₄ alkyl groups, hydroxyl groups or halogen atoms, Or a group of general formula -CH ₂ -OR _3F , wherein

R _3F is a C ₁ -C ₈ alkyl group or a phenyl group, and A _F is a group selected from the following general formula groups

as well as

Some other possible examples of di(meth)acrylates are compounds of general formula (F-V), (F-VI), (F-VII) or (F-VIII)

These compounds of the general formulas (F-I) to (F-VIII) are known and some are commercially available. See also EP-A-0 646 580 for their preparation.

Examples of commercially available products of these polyfunctional monomers are KAYARAD R-526, HDDA, NPGDA, TPGDA, MANDA, R-551, R-712, R-604, R-684, PET-30, GPO-303, TMPTA, THE-330, DPHA-2H, DPHA-2C, DPHA-21, D-310, D-330, DPCA-20, DPCA-30, DPCA-60, DPCA-120, DN-0075, DN-2475, T- 1420, T-2020, T-2040, TPA-320, TPA-330, RP-1040, R-011, R-300, R-205 (Nippon Kayaku), Aronix M-210, M-220, M- 233, M-240, M-215, M-305, M-309, M-310, M-315, M-325, M-400, M-6200, M-6400 (Toagosei Chemical Industry Company), Lightacrylate BP -4EA, BP-4PA, BP-2EA, BP-2PA, DCP-A (Kyoeisha Chemical Industry Co., Ltd.), New Frontier BPE-4, TEICA, BR-42M, GX-8345 (Daichi Kogyo Seiyaku Co., Ltd.), ASF-400 (Nippon Steel Chemical Co.), Ripoxy SP-1506, SP-1507, SP-1509, VR-77, SP-4010, SP-4060 (Showa Polymer Corporation), NK Ester A-BPE-4 (Shin-Nakamura Chemical Industry Corporation), SA-1002 (Mitsubishi Chemical Corporation), Viscoat-195, Viscoat-230, Viscoat-260, Viscoat-310, Viscoat-214HP, Viscoat-295, Viscoat-300, Viscoat-360, Viscoat-GPT, Viscoat-400, Viscoat-700, Viscoat-540, Viscoat-3000, Viscoat-3700 (Osaka Organic Chemical Industry Co., Ltd.).

It is preferred according to the invention that the radiation-curable and cationically polymerizable organic component (a) optionally comprises at least one component (a1) which is a polyfunctional aliphatic, cycloaliphatic or aromatic glycidol base ethers having at least 3 epoxy groups per molecule. Component (a1) can improve the sidewall surface quality of the cured article and the wet recoatability of the liquid composition. More preferred compositions comprise component (a1) which is a polyfunctional aliphatic, cycloaliphatic or aromatic glycidyl ether having at least 3 epoxy groups per molecule and an epoxy equivalent weight (EEW) between 100 ~2000. More preferably, their EEW is between 100-800. As an example, Shell's Heloxy 48, a trimethylolpropane triglycidyl ether having an EEW of about 140-160, is one of the most preferred polyglycidyl ether compounds. The polyfunctional glycidyl ether having at least 3 epoxy groups in the molecule can account for about 2 to 90 wt % of the entire cationic component in the composition, more preferably about 5 to about 60 wt %, most preferably about 7-40wt%.

It is preferred according to the invention that the radiation-curable and cationically polymerizable organic component (a) comprises at least one component (a2) which is a cycloaliphatic/alicyclic compound having at least 2 epoxy groups per molecule family of polyepoxides. More preferred compositions comprise component (a2) with a monomeric purity greater than 80%. As an example, 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate (ECEC) is available in various purities from various commercial sources. Preferred is Araldite CY179 (Ciba-Geigy Specialty Chemicals), which is an ECEC containing a dimer or oligomer content of about 10% or less. More preferred is UVR6105, manufactured by Union Carbide, which is an ECEC with a lower percentage of oligomers than Araldite CY 179. The viscosity decreases with increasing purity of component (a2). The Applicant has found that a higher purity and lower viscosity range of component (a2) leads to an improved exposure speed of the overall liquid composition. Preferred compositions comprise 10 to 80% by weight of component (a2). More preferred compositions comprise 20 to 75% by weight of component (a2). The most preferred compositions comprise 25 to 70% by weight of component (a2).

It is preferred according to the invention that the radiation-curable and cationically polymerizable organic component (a) optionally comprises at least one component (a3) which is a solid or Liquid epoxy phenol novolac or epoxy cresol novolac. The epoxy equivalent of component (a3) is 100-400 g/equivalent. The preferred amount of component (a3) is from 3 to 80 wt%. A more preferred amount is between 6 and 75 wt%. The most preferred amount is between 10 and 40 wt%.

Preferred vinyl ethers are those having aliphatic, aromatic or cycloaliphatic moieties in the molecule. Preference is also given to hydroxy-functional vinyl ethers. The vinyl ether component is preferably used in an amount ranging from 1 to 40 wt%. More preferably, the amount is between 3 and 30 wt%. The optimal amount is between 4 and 20 wt%.

According to the present invention, it is preferred that the radiation-curable and radically polymerizable organic component (e) is contained in the composition in an amount of 0.5-40% by weight. More preferred compositions comprise 7 to 30% by weight of component (e). Most preferably, the composition comprises between 8 and 20% by weight of component (e). Most preferred compositions comprise 4 to 10 wt% of at least one liquid or solid multi(meth)acrylate having a (meth)acrylate functionality greater than 2, and 4 to 10 wt% of one or more di(meth)acrylates Acrylate.

It is preferred according to the invention that the radiation curable composition optionally comprises 0.5 to 30% by weight of at least one solid or liquid polyol component (f). More preferred compositions comprise component (f) comprising aliphatic compounds with polyester, caprolactone, polyether, polyalkylene, polysiloxane groups and/or polyhydrocarbon segments or mixtures thereof. or alicyclic polyols. The most preferred composition comprises a polyol component (f) comprising: a substance having an aromatic carbocyclic ring in its molecule, especially a phenolic compound having at least 2 hydroxyl groups, having at least 2 Hydroxyl groups reacted with ethylene or propylene oxide or phenolic compounds having ethylene oxide or propylene oxide, aliphatic hydroxy compounds having not more than 80 carbon atoms, having at least 1 hydroxyl group and at least 1 compounds with epoxy groups, or mixtures thereof. The more preferred content of polyol component (f) is 3-30 wt%, and the most preferred content is 5-25 wt%.

The component (b) contained in the preferred composition is a cationic photoinitiator or a mixture of multiple cationic photoinitiators, and the amount used is between 0.1 and 12 wt%. More preferred compositions comprise 0.2 to 9% by weight of component (b). Most preferred compositions comprise 0.25 to 8% by weight of component (b). Preferably, component (d) is a free radical photoinitiator or a mixture of several free radical photoinitiators, and the content is between 0.1 and 10 wt%. More preferred compositions comprise 0.3 to 5% by weight of component (d). Most preferred compositions contain 0.4 to 4 wt% component (d).

Preferred, more preferred and most preferred compositions may contain 0 to 10 wt% additives or reactive diluents.

The novel compositions according to the invention also comprise a triglycidyl ether cation-reactive modifier (component c)). The cationic reactive modifier component provides flexibility and impact resistance to the cured article without compromising the exposure speed of the liquid composition or the water repellency of the cured article. Triglycidyl ether of polypropoxylated glycerol having the following structure is commercially available under the tradename ^Heloxy® 84 from Shell Corporation (Houston, Texas):

The modifier preferably comprises from about 0.5% to about 30% by weight of the total composition, more preferably from about 1% to about 30% by weight, most preferably from about 2% to 30% by weight.

The novel composition may comprise as component f) at least one compound selected from the group consisting of dihydroxybenzene, trihydroxybenzene and compounds of general formula (D-I):

Wherein R _1D and R _2D are hydrogen atoms or methyl groups;

Compounds of general formula (D-II):

Wherein R _1D and R _2D are each a hydrogen atom or a methyl group;

R _3D and R _4D are all independently of each other a hydrogen atom or a methyl group, and

xD and yD are independently integers of 1 to 15;

Trimethylolpropane, glycerol, castor oil and compounds of general formula (D-III) and (D-IV):

Wherein R _5D is an unbranched or branched (zD)-valent C ₂ -C ₂₀ alkane residue, preferably (zD)-valent C ₂ -C ₆ alkane residue,

All R _6D groups, independently of each other, are hydrogen atoms or methyl groups,

zD is an integer from 2 to 4,

vD is an integer from 2 to 20; and also

Compounds of general formula (D-VI), (D-VIII), (D-IX) and (D-X):

R _8D -(C ₃ -C ₂₀ alkylene) -R _8D (D-VIII),

wherein R _7D , R _9D and R _10D are each a hydrogen atom or a methyl group, and

Each R _8D is a group selected from groups of general formula (D-XI), (D-XII), (D-XIII) and (D-XIV):

The compounds of the above general formulas (D-I), (D-II), (D-V), (D-VI) and (D-IX) are preferably the corresponding 1,4-derivatives or bis-1,4-derivatives. Compounds of general formulas (D-I) to (D-X) and methods for their preparation are known to those skilled in the art.

The optional polyol component may consist of (D2) phenolic compounds having at least 2 hydroxyl groups reactive with ethylene oxide, propylene oxide, or with ethylene oxide and propylene oxide , especially compounds of general formula (D-IIa):

Wherein R _1D and R _2D are hydrogen ions or both are methyl groups;

R _3D and R _4D are each independently of each other a hydrogen atom or a methyl group, and

Each of xD and yD is an integer of 1-15.

The polyol component f) may also comprise: hydroxyl-containing polyester compounds prepared by esterification of at least one aliphatic polyol with at least one monobasic acid, polybasic acid or phenol, and at least one lactone Hydroxyl-containing polyester produced by the esterification reaction between a compound and at least one monobasic acid, polybasic acid or phenol. As the aliphatic polyhydric alcohol, for example, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, Glycol, polypropylene glycol, trimethylolpropane, glycerin, pentaerythritol, and dipentaerythritol. As the monobasic acid, formic acid, acetic acid, butylcarboxylic acid, and benzoic acid can be used, for example. As the polybasic acid, for example, adipic acid, terephthalic acid, phthalic anhydride, and trimellitic acid can be used. As the phenol, for example, phenol, p-nonylphenol, bisphenol A and bisphenol F can be used. As the lactone, for example, β-propiolactone and ε-caprolactone can be used. Other suitable compounds include caprolactone based oligomers - and polyesters such as triesters of trimethylolpropane and caprolactone - Tone 0301 and Tone 0310 or the Tone 02xx series ex Union Carbide.

As the polyester polyol, Bayer's Desmophen series, King Industries' K-Flex series, Ruco Polymers' Rucoflex series, Witco's Fomrez series, and Solvay's Capa series can also be used. Polyesters containing hydroxyl groups can be used alone or in combination of two or more, depending on the required properties. The optional polyol component may also contain hydroxyl functional polyether alcohols such as alkoxylated trimethylolpropane, alkoxylated bisphenol A, alkoxylated bisphenol F, known as polytetramethylene glycol Polytetramethylene ether (molecular weight between 250 and 9000), especially propoxylated, isopropoxylated and ethoxylated compounds, polyethylene glycol-200 or -600, etc. Polyether alcohols also include Bayer's Desmophen U&L and Mutranol series, Dow Chemical's Voranol series and Arco's Arcol series (LHT28, LHT42, E786). The polyol should preferably have a molecular weight of about 100-2000, more preferably about 160-1000. The polyol content can be between 0.5-30wt%.

It has hitherto been generally accepted that compounds containing hydroxyl groups are indispensable components of epoxy hybrid compositions used in stereolithography. It is believed that unless certain percentages of diols, triols or polyols are included in the composition, epoxy formulations will not cure and postcure to a high degree. The presence of diols or polyols is believed to be a major factor in obtaining UV cured articles with excellent mechanical and thermomechanical properties. The hydroxyl group reacts with the epoxy group during the ring opening of the epoxy ring, thereby contributing to the formation of the three-dimensional network. The most recent application WO 97/38354 (1997-10-16), granted to DSM Corporation, Japan Synthetic Rubber Corporation, Japan Fine Paint Corporation, reported that the diol or triol or polyol component must be higher than a certain critical content Concentrations exist in mixed liquid compositions. The patent also declares, "If the proportion of the polyol component is too low, the purpose of forming photocurable properties will not be achieved, and it will be the case that a three-dimensional film with sufficient stability in shape and performance cannot be produced from this resin composition. thing".

If necessary, the resin composition for stereolithography of the present invention may further contain an appropriate amount of other materials as long as the effects of the present invention are not impaired. Examples of such materials include radically polymerizable organic substances other than the above-mentioned cationically polymerizable organic substances; heat-sensitive polymerization initiators; additives for various resins such as colorants such as pigments and dyes, antifoaming agents, Leveling agents, thickeners, flame retardants and antioxidants; fillers such as silica, alumina, glass powder, ceramic powder, metal powder and modifier resins. Specific examples of radically polymerizable organic substances include, but are not limited to, heat-polymerizable compounds, and examples of heat-sensitive polymerization initiators include aliphatic onium salts disclosed in Japanese Patent Laid-Open Nos. 49613/1982 and 37004/1983.

Fillers that can be used in the present invention are active or inactive, inorganic or organic, powdered, fibrous or flaked materials. Examples of organic fillers are polymeric compounds, thermoplastics, core-shell, aramid, Kevlar, nylon, cross-linked polystyrene, cross-linked poly(methyl methacrylate), polystyrene or polypropylene , Cross-linked polyethylene powder, cross-linked phenolic resin powder, cross-linked urea-formaldehyde resin powder, cross-linked melamine resin powder, cross-linked polyester resin powder and cross-linked epoxy resin powder. Examples of inorganic fillers are glass and silica beads, calcium carbonate, barium sulfate, talc, mica, spherical bubbles such as glass or silica, zirconium silicate, iron oxide, glass fiber, asbestos, diatomaceous earth, dolomite , metal powder, titanium dioxide, pulp powder, kaolin, modified kaolin, hydrated kaolin metal and other fillers, ceramics and composite materials. Mixtures of organic and/or inorganic fillers may also be used.

Further examples of preferred fillers are microcrystalline silica, crystalline silica, amorphous silica, alkali aluminosilicates, feldspar, wollastonite, alumina, aluminum hydroxide, glass powder, trihydrate Alumina, surface-treated alumina trihydrate, aluminosilicates. Each of the aforementioned preferred fillers is commercially available. The most preferred fillers are inorganic fillers such as imsilica, Novasite, mica, amorphous silica, feldspar and alumina trihydrate. Mica is very attractive as a filler because it exhibits a low tendency to precipitate out of photocurable compositions. It is transparent to UV light, has a low tendency to refract or reflect incident light and it offers excellent dimensional stability and heat resistance.

The filler used in the stereolithography resin composition of the present invention must satisfy the requirements that it does not interfere with cationic polymerization or radical polymerization, and that the filled SL (stereolithography) composition has a low viscosity suitable for the stereolithography method. These fillers may be used alone or in admixture of 2 or more, depending on required properties. The fillers used in the present invention can be neutral, acidic or basic. The filler particle size can vary depending on the application and the required resin properties. It can be between 50nm and 50μm.

The fillers may optionally be surface treated with various coupling agent compounds. Examples include methacrylatepropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and methyltriethoxysilane base silane. Most preferred coupling agents are available from Osi Chemical Company as well as other chemical suppliers.

The filler is preferably used in an amount of about 0.5 to about 90%, more preferably about 5 to about 75%, most preferably about 5 to about 60% by weight, based on the total weight of the filled resin composition.

The novel composition can be prepared according to known methods, for example by premixing the individual components and then mixing the premix, or by mixing all the components using conventional equipment such as a stirred tank in the dark and, if required, at a slightly elevated temperature .

The novel composition can be polymerized by irradiation with actinic light, for example by means of electron beams, X-rays, ultraviolet or visible light, preferably with radiation having a wavelength between 280 and 650 nm. Especially suitable are laser beams, including HeCd, argon or nitrogen, but also metal vapor and NdYAG lasers. The present invention covers all existing or developing lasers of various types that can be used in stereolithography methods, such as solid-state, argon-ion, helium-cadmium lasers, etc. A person skilled in the art understands that for each light source chosen, a suitable photoinitiator must be selected and, if appropriate, sensitized. It has been found that the penetration depth of the radiation in the composition to be polymerized, as well as the rate of operation, is directly proportional to the absorption coefficient and concentration of the photoinitiator. In stereolithography, preference is given to using those photoinitiators which generate the greatest number of radical-forming or cationic particles and allow the deepest penetration of the radiation into the composition to be polymerized.

The invention also relates to a method of producing a cured article, wherein a composition as described above is subjected to actinic radiation treatment. For example, the novel compositions can be used in this case as adhesives, as coating compositions, as photoresists, for example as solder resists or for rapid prototyping, but especially for stereolithography shaping. When the novel mixture is used as a coating composition, clear and hard coatings are formed on wood, paper, metal, ceramic or other surfaces. The coating thickness can vary over a wide range, for example from 0.01 mm to about 1 mm. With the novel mixtures, relief images for printed circuits or printing plates can be produced by direct radiation of the mixture, for example by means of computer control, laser beams of suitable wavelength, or by means of photomasks and suitable light sources.

A specific embodiment of the above-mentioned method is a method for preparing a three-dimensional shape product by stereolithography, wherein the product is produced by using the novel composition as a raw material by repeatedly implementing two steps (a) and (b) alternately; step 1 ( a) a layer of the composition, one boundary of which is the surface of the composition, curing takes place at the level of the layer by irradiation with suitable rays in the area of the surface corresponding to the required cross-sectional area of the article of complex shape to be formed; In the second step (b), a new layer of liquid radiation curable composition is covered on the cured layer, and then the sequence of steps (a) and (b) is repeated until an article with a desired shape is formed. In such a method, the radiation source used is preferably a laser beam, which is especially preferably computer-controlled.

In general, the above-mentioned initial radiation curing, during which a so-called green model is obtained which does not yet exhibit sufficient strength, is followed by a final curing by heating and/or further radiation.

The term "liquid state" used in this application is equivalent to "liquid state at room temperature" in the absence of any statement to the contrary. temperature.

Example:

Typical embodiments of the present invention will be given below as examples, but the present invention is by no means limited thereto. In Example 1 below, all parts are by weight.

Base resin SL 5210, supplied by Ciba-Geigy Specialty Chemicals, Los Angeles, CA, is a blend of multifunctional epoxy resins, vinyl ether resins, and polyacrylate blends. The cationic reactive modifier was Heloxy 84, a triglycidyl ether of glycerol with an extended segment of 8 isopropoxyl mers. Heloxy 84 is commercially available from Shell (Houston, Texas). Polyarylether polyol active modifier PEPO is a copolymer or homopolymer of bisphenol A and epichlorohydrin. It is commercially available under the tradename PaphenPKHM-85X, supplied by Phenoxy Specialty Chemicals, NC. Based on information from the manufacturer, it is believed to be a mixture of solid polyether polyol Paphen with liquid commercially available polyols.

The preparation of the formulations given in the examples includes: the components are stirred and mixed according to the viscosity of the different components at 20-80° C. until a homogeneous composition is obtained. Most compositions are mixed at room temperature of about 25-30°C. Physical data on the formulations were obtained as follows:

The mechanical properties of the formulations were measured on three-dimensional samples prepared by means of a He/Cd laser. Specifically, on a 3D Systems SL 250/30 stereolithography machine, using a Helium-cadmium laser emitting 325nm laser light, samples such as window plates (for determining exposure speed), dog bones (sub-ring shapes), and Izod impacts were prepared . For determination of elongation at break, four 12 cm long dog bone samples were prepared. Impact-resistant strips, 0.15 inches thick, and cut on an automatic cutting machine. Canine bone and Izod impact strips were post cured with UV energy for 90 minutes on conventional UV post-treatment equipment.

The sensitivity of the formulations was determined using so-called window plates. In this measurement, a single layer sample is formed using different laser energies, and the thickness of the resulting layer is measured. A "working curve" is obtained by plotting the thickness of the formed layer against the logarithm of the radiant energy applied. The slope of this curve is called Dp (in millimeters or mils). The energy value at the point where the curve crosses the x-axis is called Ec (the energy at which the material is just still able to gel; see, P. Jacobs, "Rapid Prototyping", Society of Manufacturing Engineers, 1992, p. 270 et seq.).

Example 1

Liquid Composition 1 comprised 100% base resin. Liquid compositions 2 and 3 were prepared by mechanically mixing 17% Heloxy 84 or Paphen 85X with 83% base resin respectively, and then stirring the mixture at 45°C for 3 hours. Subsequently, all 3 liquid compositions were evaluated using a helium-cadmium laser on a stereolithography machine SL 250/30. The test data are presented in Table 1.

Table 1 Resin serial number Dp, mil Ec(mJ/cm ² ) Elongation at break, % Izod Impact Strength, ft.lb/in 1 base resin 5.43 7.80 1.20 0.35 2 RCM 6.14 6.53 8.5 0.65 3 PEPO 5.88 5.56 18 0.84

As can be seen in Table 1, Resin 2, due to the inclusion of the cationic active modifier, exhibits a more than 7-fold improvement over the selected base resin 1 . Moreover, Izod impact strength is also improved by 85% compared to the base resin. Similarly, Resin 3, comprising PEPO, exhibited a 15-fold improvement in elongation at break relative to the base resin, and a 140% improvement in Izod impact strength. With the reactive modifiers described above, improvements in elongation or impact resistance are not obtained at the expense of a reduction in exposure speed, however, the addition of traditional tougheners often results in such reductions. Conversely, the exposure speed has also increased. Table 1 shows that Resins 2 and 3, containing cationically active modifiers and PEPO-containing compounds, respectively, have higher Dp values than base resin 1 and lower Ec values. These figures demonstrate that toughened modified resins containing cationic active modifiers or PEPO exhibited higher exposure speeds than the base resin.

Claims (13)

1. A liquid radiation curable composition for the manufacture of three-dimensionally shaped articles, comprising: a) 20-90% by weight of an organic compound curable by actinic radiation and capable of cationic polymerization; b) 0.05～12wt% cationic photoinitiator; c) 0.5 to 30 wt% of at least one cationic active modifier represented by the following formula

d) 0～10wt% free radical photoinitiator; e) 0 to 40% by weight of free radical curable components containing at least one mono- or polyacrylate and/or methacrylate; f) 0.5～30wt% polyhydric alcohol; And g) 0-10 wt% customary additives. 2. The composition according to claim 1, wherein the actinic radiation-curable and cationically polymerizable organic substance comprises 10 to 80% by weight of at least one solid or liquid cycloaliphatic polyepoxide having at least 2 epoxy groups , and its epoxy equivalent is between 70 and 350 g/eq, or a mixture thereof. 3. The composition according to claim 1, wherein the actinic radiation-curable and cationically polymerizable organic substance comprises 3 to 70% by weight of a solid or liquid polyglycidyl ether of at least one of the following compounds: aliphatic, cycloaliphatic or Aromatic alcohols or polybasic acids, epoxy cresol novolaks, epoxy phenol novolacs, spiro-orthoester compounds, oxetane compounds, these compounds have at least 2 cationic active groups per molecule, or mixtures of these compounds. 4. The composition according to claim 1, wherein the actinic radiation-curable and cationically polymerizable organic substance comprises 0.5 to 40% by weight of at least 1 solid or liquid vinyl ether having at least 2 vinyl ether groups or at least 1 A hydroxy-functionalized vinyl ether. 5. The composition according to claim 1, wherein the composition comprises 3 to 40% by weight of a radically curable component comprising at least one mono- or polyacrylate and/or methacrylate. 6. The composition according to claim 1, wherein the cationically polymerizable organic component is a mixture comprising: at least one polyglycidyl compound or cycloaliphatic polyepoxide or aromatic ring-containing, oxirane A polyglycidyl compound of phenol novolac or epoxy phenol novolak having an average of at least 2 epoxy groups per molecule; and at least 1 vinyl ether-based resin. 7. The composition according to claim 1, wherein component f) is a liquid or solid polyol. 8. The composition according to claim 7, wherein said polyhydroxy compound comprises: a substance having an aromatic carbocyclic ring in the molecule or a phenolic compound having at least 2 hydrocarbyl groups, or having at least 2 Hydroxyl groups reacted with alkanes, propylene oxide or phenolic compounds with ethylene oxide and propylene oxide, or hydroxy compounds with at least 1 hydroxyl group and at least 1 epoxy group. 9. A composition according to claim 7, wherein said polyol comprises aliphatic, cycloaliphatic or substituted cycloaliphatic groups. 10. The composition according to claim 7, wherein said polyol is an aliphatic or cycloaliphatic or aromatic polyol with polyester, polyether, polysiloxane groups and/or polyhydrocarbon chains Festival. 11. The composition according to claim 1, wherein at least one polyfunctional acrylate and/or methacrylate has an average of 2 to 7 acrylate groups. 12. A method of producing a three-dimensionally shaped article comprising: a) subjecting a radiation-curable composition according to any one of claims 1 to 11 to treatment with actinic radiation, whereby the surface of said composition in a surface region corresponding to the desired cross-sectional area of the three-dimensional article to be formed form an at least partially cured layer on the b) covering the at least partially cured layer produced in step (a) with a new layer of said radiation curable composition, and c) Repeat steps (a) and (b) until an article of desired shape is formed. 13. The method according to claim 12, further comprising the steps of: d) Post-curing the resulting article.